CXCR6 deficiency attenuates pressure overload-induced monocytes migration and cardiac fibrosis through downregulating TNF-α-dependent MMP9 pathway

An immerging role of TNF-α in collagen synthesis and cardiac fibrosis implies the significance of TNF-α production in the development of myocardial remodeling. Our previous study showed a reduction of TNF-α and attenuated cardiac remodeling in CXCR6 knockout (KO) mice after ischemia/reperfusion injury. However, the potential mechanism of TNF-α-mediated cardiac fibrosis with pressure overload has not been well elucidated. In the present study, we aim to investigate the role of CXCR6 in TNF-α release and myocardial remodeling in response to pressure overload. Pressure overload was performed by constriction of transverse aorta (TAC) surgery on CXCR6 KO mice and C57 wild-type (WT) counterparts. At 6 weeks after TAC, cardiac remodeling was assessed by echocardiography, cardiac TNF-α release and its type I receptor (TNFRI), were detected by ELISA and western blot, collagen genes Col1a1 (type I) and Col3a1 (type III) were examined by real-time PCR. Compared with CXCR6 WT mice, CXCR6 KO mice exhibited less cardiac dysfunction, reduced expression of TNFRI, Col1a1 and Col3a. In vitro, we confirmed that CXCR6 deficiency led to reduced homing and infiltration of CD11b⁺ monocytes, which contributed to attenuated TNF-α release in myocardium. Furthermore, TNFRI antagonist pretreatment blocked AT1 receptor signaling and NOX4 expression, reduced collagen synthesis, and blunted the activity of MMP9 in CXCR6 WT mice after TAC, but these were not observed in CXCR6 KO mice. In the present work, we propose a mechanism that CXCR6 is essential for pressure overload-mediated myocardial recruitment of monocytes, which contributes to cardiac fibrosis through TNF-α-dependent MMP9 activation and collagen synthesis.     

干扰素γ抑制IL-13对成纤维细胞的纤维化作用

 目的：研究干扰素γ（IFN-γ）抑制白细胞介素13（IL-13）对成纤维细胞纤维化作用的影响。方法：将成纤维细胞分为实验组和空白对照组,实验组加入IFN-γ（4×105 U/L）和IL-13（100 μg/L）,共同作用24、48和72 h后,分别用羟脯氨酸法、RT-PCR和Western blotting检测成纤维细胞分泌胶原蛋白、I型胶原α1(Col 1A1)mRNA表达和I型胶原蛋白的表达水平。另外对比空白对照组、IFN-γ组、IL-13组和IFN-γ+IL-13组72 h后Col1A1 mRNA表达和I型胶原蛋白的表达水平。结果：MTT结果表明IFN-γ浓度增加到4×105 U/L后可显著抑制成纤维细胞的增殖（P<0.01）。羟脯氨酸法检测显示48 h和72 h实验组成纤维细胞分泌的胶原蛋白含量显著低于空白对照组（P<0.05）;RT-PCR分析结果揭示48 h和72 h实验组的Col1A1 mRNA表达水平显著低于空白对照组（P<0.05）;Western blotting检测也进一步证实了48 h和72 h实验组成纤维细胞分泌I型胶原蛋白的水平显著低于空白对照组。另外各因素组对比结果显示, 72 h后IFN-γ组Col1A1 mRNA和蛋白的表达水平显著低于空白对照组（P<0.05）,IL-13组显著高于空白对照组（P<0.05）,而IFN-γ+IL-13组显著低于显著低于其它组（P<0.01）。结论：IFN-γ可抑制IL-13对成纤维细胞的纤维化作用。     

Redifferentiation of Dedifferentiated Chondrocytes by Adenoviral Vector-Mediated TGF-β3 and Collagen-1 Silencing shRNA in 3D Culture

Autologous chondrocytes remain one of the most preferable candidates among various therapeutic cell species because of their high efficacy, despite remarkable progress in discovery and development of therapeutic cells for cartilage regenerative medicine to date. However, the essential process of cell expansion via repeated monolayer sub-cultures inevitably induces chondrocytic dedifferentiation. In this study, we aimed to achieve and enhance redifferentiation of dedifferentiated chondrocytes with dual genes of transforming growth factor (TGF)-β3 and short hairpin RNA (shRNA) that restore chondrocytic phenotype and silence fibrous collagen type I (Col I), respectively. It was hypothesized that gene delivery of the two targets would promote chondrogenesis in chondrocytes, and meanwhile inhibit the expression of the undesired Col I. Three types of recombinant adenoviruses were constructed. Two of them were of single-function vectors with the ability to express either TGF-β3 (Ad-TGFβ3) or shRNA (specific for Col I, Ad-shRNA); the third type was of double-function vectors that encode both TGF-β3 and anti-Col I shRNA (Ad-double). We infected the dedifferentiated chondrocytes with Ad-double, or co-transduced them with Ad-TGFβ3 and Ad-shRNA at the same time (designated as Ad-combination). Data from real-time RT-PCR and histological staining suggested a restoration in the expression of cartilage-specific genes including aggrecan, type II collagen, and cartilage oligomeric matrix protein (COMP); while a significant down-regulation of Col I expression was observed in groups treated with Ad-double and Ad-combination compared to other control groups. These results demonstrated that, by genetic modification, dedifferentiated chondrocytes managed to redifferentiate back to chondrocytic phenotype, which may greatly facilitate cartilage regenerative medicine by providing sufficient number of competent therapeutic cells.     

The influence of the stable expression of BMP2 in fibrin clots on the remodelling and repair of osteochondral defects

Growth factors like BMP2 have been tested for osteochondral repair, but transfer methods used until now were insufficient. Therefore, the aim of this study was to analyse if stable BMP2 expression after retroviral vector (Bullet) transduction is able to regenerate osteochondral defects in rabbits. Fibrin clots colonized by control or BMP2-transduced chondrocytes were generated for in vitro experiments and implantation into standardized corresponding osteochondral defects (n = 32) in the rabbit trochlea. After 4 and 12 weeks repair tissue was analysed by histology (HE, alcian-blue, toluidine-blue), immunohistochemistry (Col1, Col2, aggrecan, aggrecan-link protein), ELISA (BMP2), and quantitative RT-PCR (BMP2, Col1, Col2, Col10, Cbfa1, Sox9). In vitro clots were also analysed by BMP2-ELISA, histology (alcian-blue), quantitative RT-PCR and in addition by electron microscopy. BMP2 increased Col2 expression, proteoglycan production and cell size in vitro. BMP2 transduction by Bullet was efficient and gene expression was stable in vivo over at least 12 weeks. Proteoglycan content and ICRS-score of repair tissue were improved by BMP2 after 4 and 12 weeks and Col2 expression after 4 weeks compared to controls. However, in spite of stable BMP2 expression, a complete repair of osteochondral defects could not be demonstrated. Therefore, BMP2 is not suitable to regenerate osteochondral lesions completely.     

An evaluation of BMP-2 delivery from scaffolds with miniaturized dental implants in a novel rat mandible model

The purpose of this study was three-fold: (a) to develop a new small animal model to evaluate dental implant systems that recapitulates aspects of the challenging intraoral environment, (b) screen several scaffolds for in vivo bone forming efficacy when used to deliver non-glycosylated bone morphogenetic protein-2 (BMP-2) together with a miniaturized titanium (Ti) dental implant, and (c) identify correlations between in vitro BMP-2 release rates and in vivo results. The scaffolds tested were: (1) collagen-hydroxyapatite composite (Col/HA), (2) polyethylene glycol hydrogel (PEG-hydrogel), and (3) Col/HA infused with PEG-hydrogel (Col/HA/PEG-hydrogel). BMP-2 delivery directly from the Ti implants rather than from the scaffolds was also tested. MicroCT analyses at 4 weeks showed that the maximum volume and height of new bone occurred when BMP-2 (10 μg) was delivered from the Col/HA/PEG-hydrogel scaffolds. BMP-2 delivery from the Ti implant was not as effective as from the scaffolds. While in vitro BMP-2 release was highest for the PEG-hydrogel, the scaffold most successful in vivo was the Col/HA/PEG-hydrogel scaffold because it had the necessary mechanical strength to perform well in the mandibular bone environment. The in vitro release studies suggested a threshold dose of 5 μg which was borne out by the in vivo dose response studies.     

Injectable, in situ forming poly(propylene fumarate)-based ocular drug delivery systems

This study sought to develop an injectable formulation for long-term ocular delivery of fluocinolone acetonide (FA) by dissolving the anti-inflammatory drug and the biodegradable polymer poly(propylene fumarate) (PPF) in the biocompatible, water-miscible, organic solvent N-methyl-2-pyrrolidone (NMP). Upon injection of the solution into an aqueous environment, a FA-loaded PPF matrix is precipitated in situ through the diffusion/extraction of NMP into surrounding aqueous fluids. Fabrication of the matrices and in vitro release studies were performed in phosphate buffered saline at 37 degrees C. Drug loadings up to 5% were achieved. High performance liquid chromatography was employed to determine the released amount of FA. The effects of drug loading, PPF content of the injectable formulation, and additional photo-crosslinking of the matrix surface were investigated. Overall, FA release was sustained in vitro over up to 400 days. After an initial burst release of 22 to 68% of initial FA loading, controlled drug release driven by diffusion and bulk erosion was observed. Drug release rates in a therapeutic range were demonstrated. Release kinetics were found to be dependent on drug loading, formulation PPF content, and extent of surface crosslinking. The results suggest that injectable, in situ formed PPF matrices are promising candidates for the formulation of long-term, controlled delivery devices for intraocular drug delivery.     

Polymorphism of the angiotensin-converting enzyme gene and cardiovascular disease

The angiotensin-converting enzyme (ACE) is an integral part of two enzymatic cascades, one leading to the generation of angiotensin II and the other to the degradation of bradykinin. The great variety of cardiovascular effects mediated by these vasoactive peptides and the efficacy of ACE inhibitors in the treatment of hypertension and heart failure emphasize the prominent role of ACE in the cardiovascular system. Early in this decade convincing experimental evidence demonstrated the induction of this enzyme in several pathophysiological conditions, including myocardial infarction and left ventricular hypertrophy. In parallel, a deletion/insertion (D/I) polymorphism of the human ACE gene was characterized that is related to 14–50% of the interindividual variance in serum ACE activity. More recently this polymorphism has been implicated in the pathogenesis of a variety of cardiovascular disorders, including myocardial infarction, left ventricular hypertrophy, hypertension, diabetic and IgA nephropathy, carotid artery thickening, and lacunar cerebral stroke. However, the associations between the ACE D/I polymorphism and most of these conditions were found to be inconsistent when additional populations were investigated. This contribution reviews the current evidence on the relationship between the ACE D/I polymorphism and cardiovascular disease.     

A naturally derived cardiac extracellular matrix enhances cardiac progenitor cell behavior in vitro

Myocardial infarction (MI) produces a collagen scar, altering the local microenvironment and impeding cardiac function. Cell therapy is a promising therapeutic option to replace the billions of myocytes lost following MI. Despite early successes, chronic function remains impaired and is likely a result of poor cellular retention, proliferation, and differentiation/maturation. While some efforts to deliver cells with scaffolds have attempted to address these shortcomings, they lack the natural cues required for optimal cell function. The goal of this study was to determine whether a naturally derived cardiac extracellular matrix (cECM) could enhance cardiac progenitor cell (CPC) function in vitro. CPCs were isolated via magnetic sorting of c-kit⁺ cells and were grown on plates coated with either cECM or collagen I (Col). Our results show an increase in early cardiomyocyte markers on cECM compared with Col, as well as corresponding protein expression at a later time. CPCs show stronger serum-induced proliferation on cECM compared with Col, as well as increased resistance to apoptosis following serum starvation. Finally, a microfluidic adhesion assay demonstrated stronger adhesion of CPCs to cECM compared with Col. These data suggest that cECM may be optimal for CPC therapeutic delivery, as well as providing potential mechanisms to overcome the shortcomings of naked cell therapy.     

S-propranolol protected H9C2 cells from ischemia/reperfusion-induced apoptosis via downregultion of RACK1 Gene

Ischemia-reperfusion (I/R) injury can lead to apoptotic death of heart cells and subsequently heart failure. Propranolol is widely used in the management of cardiovascular disorders, but the mechanism is still unclear. Our previous studies showed that activated protein kinase C1 (RACK1) was significantly down-regulated in human umbilical vein endothelial cells by S-propranolol. RACK1 may be a target protein of S-propranolol during I/R. At present, we constructed a lentiviral expression vector for RNA interference (RNAi) of RACK1. The interference efficiency of the lentivirus was confirmed by RT-PCR and western blot. H9C2 cells infected with Lv-RACK1-shRNA or control were subjected to simulate I/R in the presence and absence of S-propranolol. The release of cytokines and chemokines was determined by ELISA assay. Flow cytometry was employed to determine mitochondrial membrane potential (MMP), Ca²⁺ concentration, reactive oxygen species (ROS) production, and cell apoptosis. We found that RACK1 RNAi and S-propranolol treatment remarkably protected I/R injured cells from apoptosis via attenuating the release of cytokines and chemokines, Ca²⁺ overload, ROS concentration, and MMP. Furthermore, RACK1 RNAi and S-propranolol, separately and in combination, significantly reduced caspase-3 activity, cytochrome c release and JNK activation. RACK 1 can be considered as a target for drug development.     

过表达肝/骨/肾型碱性磷酸酶对小鼠急性心肌梗死后心室重塑的影响

目的 探讨肝/骨/肾型碱性磷酸酶(ALPL)过表达对小鼠急性心肌梗死（MI）后心室重塑的影响。方法 36只8周龄雄性C57BL/6 J小鼠随机分为对照组(sham组),心肌梗死组（MI+Adv-EGFP组）和ALPL过表达组（MI+Adv-ALPL组）,每组12只。术后2周,使用心脏彩色超声测定小鼠心脏功能,HE染色观察小鼠心脏组织病理变化,Real-time PCR检测小鼠心脏ALPL mRNA表达水平, Western blotting检测ALPL、α平滑肌肌动蛋白（α-SMA）、Ⅰ型胶原蛋白（ColⅠ）和Ⅲ型胶原蛋白（ColⅢ）表达情况,苦味酸天狼猩红染色偏振光法测定各组标本胶原容积分数(CVF)和Ⅰ型/Ⅲ型胶原比值。结果 与MI组相比,过表达ALPL组小鼠心脏左室射血分数(LVEF)及左室短轴缩短率(LVFS)明显下降（P<0.05),过表达ALPL组HE染色可见心肌纤维断裂,排列紊乱,梗死区域纤维化明显,心脏组织α-SMA、ColⅠ、ColⅢ蛋白表达及CVF均显著增大（P<0.05）,同时ColⅠ/ColⅢ比值显著增加（P<0.05）。结论 ALPL过表达加重小鼠急性心肌梗死后心室病理性重塑。     

Human progenitor cell recruitment via SDF-1α coacervate-laden PGS vascular grafts

Host cell recruitment is crucial for vascular graft remodeling and integration into the native blood vessel; it is especially important for cell-free strategies which rely on host remodeling. Controlled release of growth factors from vascular grafts may enhance host cell recruitment. Stromal cell-derived factor (SDF)-1α has been shown to induce host progenitor cell migration and recruitment; however, its potential in regenerative therapies is often limited due to its short half-life in vivo. This report describes a coacervate drug delivery system for enhancing progenitor cell recruitment into an elastomeric vascular graft by conferring protection of SDF-1α. Heparin and a synthetic polycation are used to form a coacervate, which is incorporated into poly(glycerol sebacate) (PGS) scaffolds. In addition to protecting SDF-1α, the coacervate facilitates uniform scaffold coating. Coacervate-laden scaffolds have high SDF-1α loading efficiency and provide sustained release under static and physiologically-relevant flow conditions with minimal initial burst release. In vitro assays showed that coacervate-laden scaffolds enhance migration and infiltration of human endothelial and mesenchymal progenitor cells by maintaining a stable SDF-1α gradient. These results suggest that SDF-1α coacervate-laden scaffolds show great promise for in situ vascular regeneration.     

Migration of fibrocytes in fibrogenic liver injury

CD45(+) and collagen I-positive (Col(+)) fibrocytes are implicated in fibrogenesis in skin, lungs, and kidneys. Fibrocyte migration in response to liver injury was investigated using bone marrow (BM) from chimeric mice expressing luciferase (Col-Luc→wt) or green fluorescent protein (Col-GFP→wt) under control of the α1(I) collagen promoter and enhancer, respectively. Monitored by luciferase expression, recruitment of fibrocytes was detected in CCl(4)-damaged liver and in spleen. Migration of CD45(+)Col(+) fibrocytes was regulated by chemokine receptors CCR2 and CCR1, as demonstrated, respectively, by 50% and 25% inhibition of fibrocyte migration in Col-Luc(CCR2-/-)→wt and Col-Luc(CCR1-/-)→wt mice. In addition to CCR2 and CCR1, egress of BM CD45(+)Col(+) cells was regulated by transforming growth factor-β1 (TGF-β1) and liposaccharide in vitro and in vivo, which suggests that release of TGF-β1 and increased intestinal permeability have important roles in fibrocyte trafficking. In the injured liver, fibrocytes gave rise to (myo)fibroblasts. In addition, a BM population of CD45(+)Col(+) cells capable of differentiation into fibrocytes in culture was identified. Egress of CD45(+)Col(+) cells from BM was detected in the absence of injury or stress in aged mice but not in young mice. Development of liver fibrosis was also increased in aged mice and correlated with high numbers of liver fibrocytes. In conclusion, in response to liver injury, fibrocytes migrate from BM to the liver. Their migration is regulated by CCR2 and CCR1 but is compromised with age.     

Nrf2过表达对乙醇刺激下肝星状细胞激活与增殖及合成I型胶原的影响

 目的：探讨核因子E2相关因子2（nuclear factor E2-related factor 2,Nrf2）过表达对乙醇诱导下大鼠肝星状细胞系HSC-T6激活与增殖及I型胶原mRNA及蛋白表达水平的影响。方法：采用脂质体介导法对HSC-T6进行pEGFP-Nrf2重组质粒及pEGFP-N1空载质粒瞬时转染,将细胞分为正常对照组、乙醇刺激组、乙醇刺激+pEGFP-Nrf2质粒组和乙醇刺激+ pEGFP-N1空载质粒组。采用RT-PCR及Western blotting方法对HSC-T6中Nrf2、I型胶原及α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)mRNA及蛋白表达水平进行检测,采用MTT法对HSC-T6细胞增殖水平进行检测,采用流式细胞术对HSC-T6细胞周期分布进行检测。结果：(1) 荧光显微镜下观察显示pEGFP-Nrf2质粒成功转染HSC-T6,转染后48h Nrf2 mRNA及蛋白表达水平较其余组显著升高（P＜0.05）。(2) 乙醇刺激组与乙醇刺激+ pEGFP-N1空载质粒组之间细胞增殖水平、I型胶原、α-SMA mRNA及蛋白表达水平差异无统计学意义（P＞0.05）,均明显高于正常对照组（P＜0.05）,细胞周期分布G1期比例下降,S期比例升高（P＜0.05）,而乙醇刺激+ pEGFP-Nrf2质粒组细胞增殖水平及I型胶原、α-SMA mRNA及蛋白表达水平与乙醇刺激组及乙醇刺激+ pEGFP-N1空载质粒组相比均显著下降（P＜0.05）,细胞周期分布G1期比例显著上升,S期比例显著下降（P＜0.05）,呈G1/S期阻滞。结论：Nrf2过表达可显著抑制乙醇对HSC-T6 I型胶原及α-SMA mRNA及蛋白表达的促进作用,使HSC-T6细胞周期发生G1/S期阻滞,抑制乙醇诱导的HSC-T6增殖水平的升高,提示其对乙醇诱导的HSC-T6细胞活化具有负性调控作用。     

Proliferation, differentiation and gene expression of osteoblasts in boron-containing associated with dexamethasone deliver from mesoporous bioactive glass scaffolds

Boron is one of the trace elements in the human body which plays an important role in bone growth. Porous mesopore bioactive glass (MBG) scaffolds are proposed as potential bone regeneration materials due to their excellent bioactivity and drug-delivery ability. The aims of the present study were to develop boron-containing MBG (B-MBG) scaffolds by sol-gel method and to evaluate the effect of boron on the physiochemistry of B-MBG scaffolds and the response of osteoblasts to these scaffolds. Furthermore, the effect of dexamethasone (DEX) delivery in B-MBG scaffold system was investigated on the proliferation, differentiation and bone-related gene expression of osteoblasts. The composition, microstructure and mesopore properties (specific surface area, nano-pore volume and nano-pore distribution) of B-MBG scaffolds have been characterized. The effect of boron contents and large-pore porosity on the loading and release of DEX in B-MBG scaffolds were also investigated. The results have shown that the incorporation of boron into MBG scaffolds slightly decreases the specific surface area and pore volume, but maintains well-ordered mesopore structure and high surface area and nano-pore volume compared to non-mesopore bioactive glass. Boron contents in MBG scaffolds did not influence the nano-pore size distribution or the loading and release of DEX. B-MBG scaffolds have the ability to maintain a sustained release of DEX in a long-term span. Incorporating boron into MBG glass scaffolds led to a controllable release of boron ions and significantly improved the proliferation and bone-related gene expression (Col I and Runx2) of osteoblasts. Furthermore, the sustained release of DEX from B-MBG scaffolds significantly enhanced alkaline phosphatase (ALP) activity and gene expressions (Col I, Runx2, ALP and BSP) of osteoblasts. These results suggest that boron plays an important role in enhancing osteoblast proliferation in B-MBG scaffold system and DEX-loaded B-MBG scaffolds show great potential as a release system to enhance osteogenic property for bone tissue engineering application.     

Exendin-4 Inhibits HMGB1-Induced Inflammatory Responses in HUVECs and in Murine Polymicrobial Sepsis

Exendin-4 (EX4) has been reported to attenuate myocardial ischemia and reperfusion (I/R) injury and inflammatory and oxidative responses. Nuclear DNA-binding protein high-mobility group box 1 (HMGB1) protein acts as a late mediator of severe vascular inflammatory conditions. However, the effect of EX4 on HMGB1-induced inflammatory response has not been studied. First, we accessed this question by monitoring the effects of posttreatment EX4 on lipopolysaccharide (LPS) and cecal ligation and puncture (CLP)-mediated release of HMGB1 and HMGB1-mediated regulation of proinflammatory responses in human umbilical vein endothelial cells (HUVECs) and septic mice. Posttreatment EX4 was found to suppress LPS-mediated release of HMGB1 and inhibited HMGB1-mediated hyperpermeability and leukocyte migration in septic mice. EX4 also induced downregulation of CLP-induced release of HMGB1, production of IL-6, and mortality. Collectively, these results suggest that EX4 may be regarded as a candidate therapeutic agent for treatment of vascular inflammatory diseases via inhibition of the HMGB1 signaling pathway.     

Type I collagen cleavage is essential for effective fibrotic repair after myocardial infarction

Efficient deposition of type I collagen is fundamental to healing after myocardial infarction. Whether there is also a role for cleavage of type I collagen in infarct healing is unknown. To test this, we undertook coronary artery occlusion in mice with a targeted mutation (Col1a1(r/r)) that yields collagenase-resistant type I collagen. Eleven days after infarction, Col1a1(r/r) mice had a lower mean arterial pressure and peak left ventricular systolic pressure, reduced ventricular systolic function, and worse diastolic function, compared with wild-type littermates. Infarcted Col1a1(r/r) mice also had greater 30-day mortality, larger left ventricular lumens, and thinner infarct walls. Interestingly, the collagen fibril content within infarcts of mutant mice was not increased. However, circular polarization microscopy revealed impaired collagen fibril organization and mechanical testing indicated a predisposition to scar microdisruption. Three-dimensional lattices of collagenase-resistant fibrils underwent cell-mediated contraction, but the fibrils did not organize into birefringent collagen bundles. In addition, time-lapse microscopy revealed that, although cells migrated smoothly on wild-type collagen fibrils, crawling and repositioning on collagenase-resistant collagen was impaired. We conclude that type I collagen cleavage is required for efficient healing of myocardial infarcts and is critical for both dynamic positioning of collagen-producing cells and hierarchical assembly of collagen fibrils. This seemingly paradoxical requirement for collagen cleavage in fibrotic repair should be considered when designing potential strategies to inhibit matrix degradation in cardiac disease.     

Distribution of two HIV-1-resistant polymorphisms (SDF1-3'A and CCR2-64I alleles) in the Polish population

Chemokine receptors (CCR2 and CXCR4) are used as coreceptors for entry of human immunodeficiency virus (HIV) into the target cells. Mutations in CCR2 (CCR2-64I) and stromal-derived factor SDF1 (SDF1-3'A), the primary ligand for CXCR4, exhibited a protective effect against the onset of acquired immune deficiency syndrome (AIDS). The frequency of the SDF1-3'A and CCR2-64I alleles were determined in blood donors from 16 provinces, covering the entire territory of Poland. Of 1063 individuals, 274 (25.8%) were carriers of the SDF1-3'A allele; 36 of them (3.4%) were homozygotes (SDF-3'A/A) while 238 (22.4%) were heterozygotes (SDF-3'G/A), resulting in a 14.6% frequency of the SDF1-3'A allele. Moreover, in the same group of individuals, 234 (22.0%) carried the CCR2-64I allele; 6 of them (0.6%) were homozygotes (CCR2-64I/I), and 228 (21.4%) were heterozygotes (CCR2-64V/I), resulting in an 11.3% frequency of the CCR2-64I allele. The highest frequencies of the SDF1-3'A allele were found in the northeastern provinces and in one of the western provinces of Poland. In contrast, allelic frequencies of CCR2-64I varied slightly among different provinces. The different pattern of prevalence of the SDF1-3'A and CCR2-64I alleles in Poland might suggest that the CCR2-64I allele was spread much earlier than the SDF1-3'A allele in the population of Poland.     

Caveolae在高糖诱导的大鼠肾小球系膜细胞细胞外基质合成中的作用

 目的：探讨胞膜小凹(caveolae)在高糖(HG)诱导大鼠肾小球系膜细胞(MCs)细胞外基质(extracellular matrix,ECM)表达过程中的作用。方法：传代培养的大鼠MCs同步化后分为：(1)正常糖组;(2)HG组;(3)HG+甲基-β-环糊精(β-MCD)组;(4)HG+β-MCD+胆固醇组。用Western blotting检测小凹蛋白1(Cav-1)、磷酸化小凹蛋白1(p-Cav-1-Y14)和Ⅰ型胶原(ColⅠ)蛋白的表达水平,用实时定量PCR检测细胞中Cav-1 mRNA表达变化,用ELISA方法检测上清中纤维连接蛋白(FN)的蛋白含量。结果： (1)高糖状态下, 系膜细胞 FN和ColⅠ 蛋白表达水平均显著增加(均P<0.05)。(2)高糖培养显著增加p-Cav-1-Y14水平(P<0.01),而对Cav-1 mRNA及蛋白表达无明显影响(P>0.05)。(3)β-MCD预处理抑制了高糖诱导的 p-Cav-1-Y14升高(P<0.01)及FN表达(P<0.05),但对高糖诱导的Col I表达无影响;β-MCD的作用可被胆固醇抑制。结论：高糖可显著增加系膜细胞1型胶原及纤维连接蛋白的合成。高糖诱导的纤维连接蛋白合成与Cav-1磷酸化水平增加有关。     

Both Chondroinduction and Proliferation Account for Growth of Cartilage Nodules in Mouse Limb Bud Cultures

High density micromass culture of limb bud mesenchymal stem cells isolated from mouse embryos represents a well-established model to study chondro- and osteogenesis. In spite of wide usage of the limb bud model, the mechanisms underlying cartilage nodule growth remain unclear. To determine whether cartilage nodules grow solely by induction of surrounding cells or proliferation of cells within the nodules, we performed BrdU/Collagen II (Col II) double-labelling and 3D reconstruction of growing cartilage nodules. We demonstrated that Col II-positive replicating chondrocytes are present throughout the nodules with the majority of replicating cells localized on the top (cell-medium interface) and periphery/sides of nodules. Kinetic analysis of cellular proliferation within the nodules demonstrated the time-dependent reduction in number of Col II-positive replicating cells. The sequential expression of Col I, Col II, Col X, parathyroid hormone related peptide receptor 1 (Pthr1), bone sialoprotein (Bsp) and osteocalcin (Ocn) mRNAs was similar to that characterizing chondrocyte differentiation and maturation in vivo. We conclude that the limb bud model recapitulates events seen during endochondral bone formation: cellular aggregation, proliferation, differentiation and maturation to hypertrophy. We also conclude that not only induction of peri-nodular mesenchymal cells but also proliferation of chondrocytes within cartilage nodules contribute to cartilage nodule growth.